KR100807802B1 - Serial data communication line check device - Google Patents

Abstract

The present invention relates to an apparatus for checking a serial data communication line, and in the present invention, two lines of a communication line terminal for connecting to a communication line to be checked and a communication line terminal are selected, and a differential voltage and a bit gap between the selected lines. An analog circuit section for outputting a digital signal as a digital signal, an output section for displaying a differential voltage and a bit interval output from the analog circuit section, a key input section for receiving the type and terminal number of the communication line from a user, and input information for the key input section. Accordingly, a serial data communication line checking apparatus is provided, comprising a central processing unit for outputting a channel control signal for selecting two lines selected from the analog circuit unit, and a power supply unit for supplying power to the apparatus.

Serial data communication lines; Communication line check device

Description

Serial data communication line check device {SERIAL CABLE CHECKING APPARATUS}

1 is a block diagram of an apparatus for checking serial data communication lines according to an embodiment of the present invention.

***** Brief description of the main symbols on the drawing *****

100: communication line terminal 300: central processing unit

400: key input unit 500: power supply unit

600: analog circuit part

The present invention relates to an apparatus for checking a serial data communication line. More particularly, the present invention relates to an apparatus for checking a serial data communication line, and more specifically, to measure whether a data line maintains a voltage level at which communication is possible by measuring a voltage difference between serial communication lines. The present invention relates to a serial data communication line checking apparatus for measuring data communication bit intervals through sampling and providing characteristic information relating to whether or not communication is possible on an installed communication line.

The microprocessor can exchange information with the outside through peripheral devices. Generally, the microprocessor can be divided into two types of parallel communication and serial communication. In general, when exchanging information with devices in a computer, a high speed communication speed is generally required, and a parallel communication method that can process a lot of information at a time is mainly used.

This is because the performance of a computer can be improved by processing a large amount of information all at once in a timely manner. A typical example of this method is to increase the information throughput of the microprocessor itself, which is expressed as the number of data bits. However, in all cases, parallel communication cannot be used. The reason is that the communication distance is limited, the technical difficulties in implementation and the cost are too high. In many cases, the application itself does not require a high communication speed. For this reason, serial communication is often used when a computer communicates with the outside world.

The serial communication method is a method of transmitting and receiving data bits externally in units of one bit, and is easy to implement, can be transmitted far away, and can easily utilize existing communication lines (such as telephone lines), thereby having a large cost reduction effect. Typical examples of serial communication are modem, LAN, RS232 and X.25. However, if serial communication is largely divided, it is divided into asynchronous type and synchronous type. Asynchronous communication controllers are commonly called UARTs (Universal Asynchronous Receiver / TransmItter).

Since the signal coming out of the UART usually has a TTL signal level, it is weak in noise and limited in communication distance. The interface IC that receives this TTL signal and is strong against noise and can be sent far away is called LINE DRIVER / RECEIVER. Among them, RS232, RS422 and RS485 are representative.

In the serial communication method, the most important thing in the physical layer for intercommunication is the size and bit spacing of the data signal, and the RS232, RS422 and RS485 methods currently on the market maintain the maximum and minimum to enable communication to the standard. The communication is possible only when the voltage is specified and the data bit interval is maintained within an acceptable error range according to the communication speed in the bit interval. In order to detect the characteristics of such communication lines, Since the waveform displayed on the screen should be judged by measuring the waveform by oscilloscope, beginners have difficulty in using the oscilloscope and need specialized knowledge for accurate analysis of communication line characteristics. Because there is the possibility of expensive equipment damage and the inconvenience of moving due to the weight, it is difficult to detect the characteristics of the data communication line during the site commissioning.

The present invention is to solve the above problems, by measuring the voltage difference between the individual communication line to determine whether the data line maintains the voltage level that can communicate with the data communication bit interval through the data sampling between the communication line It is an object of the present invention to provide a general-purpose serial data communication line inspection device that is easy to carry out measurement and carry, which provides line characteristic information and failure information relating to the communication capability of an established communication line by measuring the sig- nality.

According to the present invention, an analog circuit unit for selecting two lines of a communication line terminal for connecting to a communication line to be checked and a communication line terminal and outputting a differential voltage between the selected lines as a digital signal, and a differential output from the analog circuit unit An output unit for displaying a voltage, a key input unit for receiving the type and terminal number of the communication line from a user, and a channel control signal for selecting two lines selected from the analog circuit unit according to input information of the key input unit Provided is a serial data communication line checking apparatus comprising a central processing unit and a power supply unit for supplying power to the apparatus.

In addition, in the present invention, the analog circuit portion of the serial data communication line checking device further comprises a component for sampling the differential voltages of the selected two lines and calculating bit intervals from the sampled signals. Is provided.

Hereinafter, with reference to the accompanying drawings will be described in detail the advantages, features and preferred embodiments of the present invention.

1 is a block diagram of an apparatus for checking serial data communication lines according to an embodiment of the present invention. Serial data communication line failure detection apparatus of the present invention is responsible for the control and input and output of the communication line terminal 100 for connecting to the communication line to be checked, the output unit 200 for displaying this after detecting the communication line characteristics, the inspection device The central processing unit 300 to select the line characteristic detection menu, the key input unit 400 for starting and ending the detection, the power unit 500 for supplying power to the device, and the analog circuit unit 600 for detecting the communication line characteristics. It is composed of

The analog circuit unit 600 for detecting a communication line characteristic receives a signal from the communication line terminal 100 and a signal according to a channel control signal output from the signal distributor 610 and the central processing unit 300 for distributing it to an analog switch. Differential amplifying the difference between the first analog switch 620 and the second analog switch 630 for selecting the first signal and the second signal from the signal output from the divider 610, respectively, the selected first signal and the second signal An amplifier 640, an A / D converter 650 for converting the differentially amplified signal into a digital signal for detecting the differential voltage, a differential voltage calculator 660 for calculating a differential voltage from the converted digital value, differential amplification Sampling unit 670 for sampling the received signal at regular intervals, and a bit interval calculation unit 680 for calculating the interval of the received data bits from the sampled signal.

Hereinafter, the operating principle of the serial data communication line failure detection apparatus of FIG. 1 will be described. The line to be detected is connected to the communication line terminal 100. Manually input the type of the communication line and the terminal number of the communication line connected using the key input unit 400, or select the automatic mode to automatically check all the lines in the inspection device, using the output unit 200 After confirming, press the start button. The central processing unit 300 uses the signal distribution unit 610 using information on the type and terminal number of the communication line input through the key input unit 400 or terminal number selection by order logic in the central processing unit 300. The channel selection signal is transmitted to the first analog switch 620 and the second analog switch 630 which are input through the second analog switch 620.

Two lines of the input lines are selected by the channel control signal, and the selected signals are transferred to the differential amplifier 640. The differential amplifier 640 obtains a difference voltage for two input signals, and because the difference voltage may be very small, amplifies it to a predetermined amplification ratio and sends it to the A / D converter 650 to calculate the signal size. The data is sent to the data sampling unit 670 to measure the data bit interval. The A / D converter 650 digitizes the input signal and sends it to the differential voltage calculator 660 to express the input signal size numerically. The data sampling unit 670 determines whether the data level is a high level (normal data bit '1') or a low level (normal data bit '0') by using a fast sampling frequency. The data is transferred to the bit interval calculator 680 to measure the time interval remaining at the high level or the low level, thereby calculating the data rate between the two lines. The calculated magnitude of the input signal and the data bit interval (communication speed) are shown to the user through the output unit 200. When the detection of the two selected lines is finished, the selection of the other undetected lines is made through the central processing unit 300 to detect all the lines by the same procedure.

When the serial data communication line fault detection apparatus of the present invention is connected to the RS232 communication line, a ground line is connected to the first analog switch 610, and any one of the other lines except the ground line is connected to the second analog switch 630. Check the line status by connecting. When the serial data communication line failure detection device of the present invention is connected to the RS422 communication line, the first analog switch 610 and the second analog switch 630 connect TXD + and TXD- lines, respectively, or RXD + and RXD- lines. Check the line condition by connecting. When the serial data communication line failure detection device of the present invention is connected to the RS485 communication line, the first analog switch 610 and the second analog switch 630 are connected to the TRXD + and TRXD- lines, respectively, to check the line state.

The user can determine the state of the communication line under test by measuring the differential voltage and bit spacing between the two communication lines displayed at the output. The user can confirm whether the magnitude of the received signal is within a communication range by checking whether the differential voltage displayed on the output unit 200 is a voltage difference within a normal operating range of RS232, RS422, and RS482. By identifying the bit spacing indicated in the), it is possible to confirm whether the communication speed between devices is operating within the normal range.

The voltage difference between the communication lines is digitally displayed on the output unit by the serial data communication line checking device of the present invention, so that it is easy to determine whether the communication voltage is within the allowable voltage range, and also digitally outputs the communication speed. As a result, even beginners can easily determine whether data transmission is possible depending on the communication speed allowed. In addition, it can be used to check the maximum communication speed in the already installed communication line, and it is easy to check the data communication error due to the connection error at the intermediate connection point which is difficult to grasp through the inspection at the intermediate connection point of the communication line. You can judge.

While the preferred embodiments of the present invention have been described using specific terms, such descriptions are for illustrative purposes only, and it is understood that various changes and modifications may be made without departing from the spirit and scope of the following claims. Should be done.

Claims (3)

delete A serial data communication line checking apparatus for checking a communication state of a serial data communication line for serially mediating data transmission between electronic devices, A communication line terminal for connecting with a communication line to be checked; An analog circuit unit for selecting two lines of the communication line terminals and outputting a differential voltage between the selected lines as a digital signal; An output unit for displaying the differential voltage output from the analog circuit unit; A key input unit which receives a type and a terminal number of the communication line from a user; A central processing unit for outputting a channel control signal for selecting two lines selected by the analog circuit unit according to the input information of the key input unit; And A power supply for supplying power to the apparatus, And said analog circuit portion comprises a component for sampling the differential voltages of the two selected lines and calculating bit intervals from the sampled signal. A serial data communication line checking apparatus for checking a communication state of a serial data communication line for serially mediating data transmission between electronic devices, A communication line terminal for connecting with a communication line to be checked; An analog circuit unit for selecting two lines of the communication line terminals and outputting a differential voltage between the selected lines as a digital signal; An output unit for displaying the differential voltage output from the analog circuit unit; A key input unit which receives a type and a terminal number of the communication line from a user; A central processing unit for outputting a channel control signal for selecting two lines selected by the analog circuit unit according to the input information of the key input unit; And A power supply for supplying power to the apparatus, The analog circuit portion A signal distributor which receives a signal from the communication line terminal and distributes the signal; A first analog switch for selecting a first signal from a signal output from the signal splitter according to a channel control signal output from the central processing unit; A second analog switch for selecting a second signal among signals output from the signal splitter according to a channel control signal output from the central processing unit; A differential amplifier for amplifying a voltage difference between a first signal output from the first analog switch and a second signal output from the second analog switch; An A / D converter converting the differentially amplified signal from the differential amplifier into a digital signal; A differential voltage calculator configured to calculate a differential voltage from the converted digital value; A sampling unit configured to sample the differentially amplified signal from the differential voltage calculator at regular intervals; And And a bit interval calculation unit for calculating a bit interval from the sampled signal.

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